Club 80-90 Forums

When I did my oil change yesterday, I could feel it didn't tighten up correctly (yes, new washer ). So very soon I will have to re-tap and fit another sump plug.

On checking around I found a very reasonably priced kit (£14 incl P&P) on ebay (HERE)
It is to go from the std 14mm to 15mm though, not the 16mm most folk seem to use.

Looks ok to me. Would you buy and use that kit ?

I wonder why it comes with 6 new sump plugs

I think helicoil is better as you are then screwingonto a steel thread rather thn aluminium and you keep the origional plug
I have the kit with some coils from when i did mine If you want to borrow it but I think the drill is missing so would need to get one

That ebay kit does not come will drill either by the looks ?

Also need to be careful about the overall diameter of the plug of non standard you won't get a socket on that one^^^^

Thanks for the offer might well go that route (depending on what others say about that kit)

What size drill bit (guessing 15.5 for a 16mm tap/plug) ?

itchyfeet wrote:That ebay kit does not come will drill either by the looks ?

It seems that going up just 1mm into alloy means the tap can cope without having to enlarge the hole with a drill.

itchyfeet wrote:Also need to be careful about the overall diameter of the plug of non standard

Good point, (though I wonder what the overall diameter of the usual conversion to a 16mm Renault/Citroen plug is ?)

That one in the ebay link you won't get a socket on
My spare engine has a larger m16 thread plug with an internal hex
You can also get sump plugs with smaller external hex

So basically you are buying a tap and some sump plugs you can't use

M15 is. Not a standard size

ghost123uk wrote: On checking around I found a very reasonably priced kit (£14 incl P&P) on ebay (HERE)
It is to go from the std 14mm to 15mm though, not the 16mm most folk seem to use.

Looks ok to me. Would you buy and use that kit ?

I wonder why it comes with 6 new sump plugs

Yes I always use one. It gives you a second chance to go up to 16mm if necessary. As you are not taking that much metal off with the tap you can tap it straight away.

The problem is how much material is left for a good thread

m14 external thread is 14mm max od, m15 is 15mm max od etc

An m 14 internal thread has a max thread od of 14mm to match etc

An m14x1.5 internal thread has a drilling diameter of 12.5mm and a minor thread diameter very close at 12.4mm
the thread height is 0.8mm 12.4+0.8+0.8=14mm

so when you strip out an internal m14x1.5 thread you will end up with a hole that in places is 14mm diameter or possibly larger

M15x1.5 is not a standard size but you can buy it and it has a drilling diameter of 13.5mm so you can see you wont get a full thread, You will also need a cap head type plug
having opened the thread to m15 if it fails and you want to go to m16 you will have the same problem of not a full thread.

m16 x1.5 drilling diameter is 14.5mm perfect but you wil also need a cap head type plug

m14 helicoil drilling diameter is 14.25mm perfect and you can use your existing plug

Had a helicoil in mine. It is a temporary fix and it was failing, so I had the sump re-bored and a larger plug fitted. Much better. Just don't over tighten the plug!

Ralf85 wrote:Had a helicoil in mine. It is a temporary fix and it was failing, so I had the sump re-bored and a larger plug fitted. Much better. Just don't over tighten the plug!

I dont see a helicoil as a temporary fix if its done properly it should last a vary long time
i did mine several years ago and its had many oil changes since all torqued to 25Nm
as you say the killer of threads is not the thread but the owners

how many people bother to torque the plug ?
a low range torque wrench is around £20 from machine mart

itchyfeet wrote:I think helicoil is better as you are then screwing onto a steel thread rather than aluminium and you keep the original plug

I have decided to take your advice and Helicoil it. As you say, it does seems a better solution than that kit.

itchyfeet wrote:I have the kit with some coils from when i did mine If you want to borrow it

May I take you up on that offer ?

itchyfeet wrote:but I think the drill is missing so would need to get one

From the info in your post I see the correct drill would be 14.25mm but I don't think you can buy one of that size, what size would you use ?

Many thanks,
John

E D I T = that was meant to be a pm, but I don't suppose it matters, so I'll leave it here

ps, just "so I know" (as I like to know stuff) what pitch is the std 14mm sump plug ?

Yeh of course you can borrow it, PM me your address and I will post it, just post it back when you are done.

I used a 14mm drill as you are hand drilling it it will end up slightly bigger I think but many domestic drill chucks wont go that big, worth checking the size of yours.

I have found a 13.8mm drill with the shank turned down to fit a 10mm chuck, I'm going to test it in a lump of ally after I have finished my lunch, I think it will be OK

pitch is fine = 1.5mm

Just an FYI once you repair it you may want to think about using a pump like a pella to remove the oil via the dipstick hole. I purchased on some years back and it saves so much hassle when doing a n oil change

On its way
This drill I have is knackered its drilling oversize I think its warped
Id get a brand new one
Reduced shank type are called blacksmiths drills I think
I strongly reccomend test drilling a piece of ally first and tap it for practice

Most of the swarf will fall out but id flush with old engine oil before fitting the coil

Good luck and please don't blame me if it goes pearshaped

itchyfeet wrote:On its way
This drill I have is knackered its drilling oversize I think its warped
Id get a brand new one
Reduced shank type are called blacksmiths drills I think
I strongly reccomend test drilling a piece of ally first and tap it for practice

Most of the swarf will fall out but id flush with old engine oil before fitting the coil

Good luck and please don't blame me if it goes pearshaped

I always use grease on the tap for something like that - it catches virtually all the swarf. Just have to be careful that it doesn't hold a piece causing a dodgy thread, I do 1/4 turn then back off. Slow but sure.
Yes they are called blacksmiths drills, I did have a few amongst my stock but they were all imperial!